package jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class JDBCDemo6 {
    public static void main(String[] args) {
        try (
                Connection con = DBUtil.getConnection()
        ) {
            Statement sat = con.createStatement();
            String sql = "SELECT COUNT(*) count "+
                         "FROM class c " +
                         "JOIN student s ON c.id = s.class_id " +
                         "WHERE c.name = '1年级1班' ";
            ResultSet rs = sat.executeQuery(sql);
            while (rs.next()){
                int count = rs.getInt("count");
                System.out.println("人数:"+ count);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}
